Integrated flange seal electrical connection

ABSTRACT

Disclosed herein are a method and an apparatus for providing a high efficiency seal in an electrical connector. The seal provides an impediment to the passage of fluid at one end of the electrical connector to the environment at the other end of the electrical connector. The electrical connector may be incorporated into an over-mold that contains other components. The electrical connector achieves the highly efficient seal through a combination of a dual torturous path design, incorporation of melt ribs, and may further involve the technique of impregnation.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional patent application of U.S. patent application Ser.No. 10/206,584 filed Jul. 26, 2002, now U.S. Pat. No. 6,821,162.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a connector for interconnection of electricaldevices, where the connector provides an impediment to the passage offoreign material.

2. Brief Description of Prior Developments

Various methods have been used to seal electrical connectors installedin penetrations to liquid fuel tanks. Known techniques include use ofwashers, o-rings, and other similar structures. One other technique usesa “torturous path” incorporated into a plastic connector.

The torturous path technique relies upon a series of ribs, or similarfeatures to limit the migration of a fluid or gaseous component from oneend of the sealed electrical connector to the other. This techniquemakes use of a path filled with twists and turns that restrict the flow.An example of a component using the torturous path technique is a 2×2Fuel Header available from the assignee of this patent application,which provides for a torturous path between the electrical conductor pinand the material forming the connector body. While this technique isadequate for many applications, it may be desirable to provide anelectrical connector having greater resistance to fluid or vaporpassage.

What is needed is a highly effective technique for sealing electricalconnectors.

SUMMARY OF THE INVENTION

The foregoing and other problems are overcome by methods and apparatusin accordance with embodiments of this invention.

Disclosed herein in terms of the preferred embodiment is a technique forproviding an electrical connection device characterized by a highlyeffective seal against the migration of foreign matter including, butnot limited to fluids such as liquid, gaseous, or vapor form materials,or components thereof. For convenience, aspects of the invention areherein referred to as a “flange electrical connection” or FEC. The FECmay be integrated into a flange seal that contains other devices, suchas fuel lines. A flange seal that contains a FEC in combination withother devices is referred to herein as an “Integrated Flange Seal,” orIFS. Although the FEC may ultimately be an element of an IFS, thedisclosure herein focuses upon the FEC, and aspects of the FEC.

In the disclosure provided herein, the FEC is discussed in terms of anelectrical connection to a fuel tank, where the tank contains ahydrocarbon based fuel. Those skilled in the art will recognize that theinvention disclosed herein may be used in other embodiments to protectagainst the transmission of matter foreign through the electricalconnector, including fluids such as liquids, vapors or gases, withoutdeviating from the teachings disclosed herein.

In accordance with an aspect of this invention, the FEC incorporates adual torturous path design. As used herein, the “torturous path” designinvolves a series of twists and turns, or other similar features incertain elements of the FEC. Once assembled, the twists and turns serveto create a torturous path between the body of the electrical connectorand the internal electrical conductors, and the body of the electricalconnector and the external structure (i.e. over-mold), therebyeffectively limiting the passage of foreign matter through and aroundthe connector body.

In accordance with another aspect of this invention, the FEC furtherincorporates melt ribs. As used herein, “melt ribs” include any plasticmolding technique where added plastic features are used to create a sealupon the application of a sufficient amount of thermal energy to the FECmaterials.

In accordance with another aspect of this invention, the FEC furthermakes use of the manufacturing technique known as impregnation. As usedherein, “impregnation” refers to any technique involving a decompressioncycle intended to eliminate gas (air) bubbles or other imperfections insealing materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The above set forth and other features of the invention are made moreapparent in the ensuing Detailed Description of the Invention when readin conjunction with the attached Drawings, wherein:

FIG. 1 is a perspective view of one embodiment of the FEC incorporatedinto a penetration seal cover, which supports other devices including afuel line.

FIG. 2 is a perspective view of an electrical conductor used within theFEC.

FIG. 3 is a side view of the electrical conductor used within the FEC.

FIG. 4 is an exploded view of a portion of the electrical conductor usedwithin the FEC.

FIG. 5 is a diagram of the electrical conductor used within the FEC ofFIG. 1, rotated 90° from the view shown in FIG. 3.

FIG. 6 is a perspective view of a pre-mold electrical connector prior tofinal molding.

FIG. 7 is a side cross-sectional view of the pre-mold connector.

FIG. 8 is a front view of the pre-mold connector.

FIG. 9-1 and FIG. 9-2, collectively referred to as FIG. 9, illustrates amagnified portion of the electrical connector of FIG. 6, where melt ribsare incorporated into the electrical connector.

FIG. 10 is a cross sectional view of a portion of the Integrated FlangeSeal, IFS, showing the incorporation of the pre-mold connector of FIGS.6-9.

The drawings provided herein are considered only to be exemplary andillustrative of embodiments of the FEC, and are not to be consideredlimiting of the FEC.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 shows a perspective view of a flange electrical connector 100,also referred to herein as a FEC 100, incorporating features of thepresent invention. In the preferred embodiment described herein, the FEC100 is incorporated into an Integrated Flange Seal 1, or IFS 1, intendedfor use in an automobile. In alternate embodiments, the FEC 100 providesa barrier to other foreign matter, which may include fluids such asliquid, gaseous or vapor form material. Although the present inventionwill be described with reference to the exemplary embodiment shown inthe drawings, it should be understood that the present invention can beembodied in many alternate embodiments. For example, any suitable size,shape, or type of elements or materials could be used.

The FEC 100, in this embodiment, is used for providing electricalconnection with conventional devices located within a fuel tank (notshown), such as a fuel level sensor or an electrically driven fuel pump.The fuel tank devices are not shown, or described herein. It should beunderstood that the FEC 100 may be designed and constructed so as toprovide for a variety of electrical connections as needed. For example,the FEC 100 may contain single or multiple electrical conductors, andthe electrical conductors may further have distinctly differentelectrical properties. The actual configuration of the FEC 100 isdependent upon many factors, including by not limited to, the needs ofthe user.

In the preferred embodiment, the FEC 100 is capable of achieving verylow transmission levels of hydrocarbons. The term “very low” means thatthe FEC 100 is capable of impeding the passage of hydrocarbon fuel, andthe fuel components, to a level that is either a fraction of thequantity achieved by conventional connectors, or alternatively, “verylow” means the FEC 100 is capable of reliably meeting specificationsimposed by applicable regulation for the limitation of passage ofhydrocarbons (or other fuel components). Expressed another way, the FEC100 provides a “highly effective” seal impeding the passage ofhydrocarbon fuel, and hydrocarbon based fuel components.

In one embodiment of the FEC 100 as disclosed herein, where the FEC 100includes only the dual torturous path, the helium leak rate through theFEC was about 10⁻⁴ cc/min. In another embodiment, where melt ribs alsowere used in the FEC 100, the helium leak rate ranged from about 10⁻⁵cc/min to about 10⁻⁷ cc/min. In the embodiment using impregnation, thehelium leak rate was about 10⁻⁸ cc/min.

This disclosure includes teachings related to: aspects of electricalconductors assembled and incorporated into a pre-mold electricalconnector FEC 100; aspects of the pre-mold electrical connector FEC 100;and aspects of the post-mold IFS 1.

The Electrical Conductor

FIG. 2 shows an electrical conductor 20 used in the FEC 100. Theelectrical conductor 20 is characterized by a series of ribs 25. Theribs 25 are incorporated to provide a “torturous path” for fluids whenthe pre-molded connector body is molded over the electrical conductor20. For purposes of this invention, a fluid (fluids) may be a liquid,gas or vapor, or a combination-thereof. The fluid that is sealed againstmay be considered undesirable foreign material.

The torturous path technique relies upon a series of ribs 25, or similarfeatures, to provide a series of twists and turns that effectivelyrestrict flow of fluid between the electrical conductor 20 and thematerial in the body of the electrical connector. The appearance andcharacter of the series of ribs 25 is dependent upon a variety offactors, including but not limited to, temperature, pressure, andviscosity of the fluid. In this embodiment, the electrical conductor 20is coined from a copper alloy and is further dipped in hot tin. Theelectrical conductor 20 in this non-limiting embodiment has about 80%electrical conductivity, or greater.

The electrical conductor 20 has electrical contacts at each end. At thetop end, the electrical conductor 20 has an electrical contact that isreferred to herein as a male contact 21. At the bottom end of theelectrical conductor 20, an electrical contact is included that isreferred to herein as a flap style contact 22. The flap style contact 22is set in a V shape, where the flaps make reliable electrical contactwhen subsequently wrapped or crimped over a wire or other suitableelectrical device.

FIG. 3 shows the electrical conductor 20 from a frontal view. Thetopmost portion of the electrical conductor 20 includes the male contact21. FIG. 3 provides a more detailed view of the electrical conductor 20.In this embodiment, the electrical conductor 20 includes at least sixribs 25 included to provide a torturous path for protection against themigration of fluids from one end to the other end of the electricalconductor 20. In other embodiments, the series of ribs 25 may be limitedto at least one rib. The characteristics chosen for the series of ribs25 depends upon a variety of factors, including but not limited to,temperature, pressure and viscosity of the fluid.

FIG. 4 provides an exploded view of a portion of the electricalconductor 20. The view in FIG. 4 shows permissible distortion 38 in therib 25 components of the electrical conductor 20. These appear as convexand concave distortions 38 in the surface of the electrical conductor20. These distortions 38 serve to further improve the effect of thetorturous path technique. In other embodiments, features, such as butnot limited to, convex or concave distortions 38, appear and are used toenhance the features included for provision of a torturous path.

FIG. 5 provides a side view of the electrical conductor 20. The malecontact 21 is shown pointed downward, as the electrical conductor 20 isshown in a horizontal position. A 90° bend is shown, the bend includedfor directing the electrical conductor 20 downward when the electricalconductor 20 is incorporated into the FEC 100. FIG. 5 shows that theribs 25 are visible from the side. When taken in combination with theperspective provided in FIG. 3, it can be seen that the ribs 25 arepronounced around the exterior surface of the electrical conductor 20.Once assembled as a FEC 100, the incorporation of ribs 25 thatcircumscribe the electrical conductor 20 provides a torturous path forfluid migrating along the electrical conductor 20, regardless of thepath taken.

FIG. 5 also shows the electrical contacts at the bottom of theelectrical conductor 20 that are referred to as the flap style contact22. In this embodiment, the flap style contact 22 is used to provide apermanent type of connection, where installation involves bending orcrimping of the flap style contact 22 over an electrical conductor. Inthis embodiment, breaking the electrical connection is most convenientlyachieved by unclipping and/or slipping off a female contact that mateswith the male contact 21. In other embodiments, other styles ofelectrical connectors are incorporated into the electrical conductor 20,in place of or in addition to the male contact 21 and/or the flap stylecontact 22. For example, a female connection is incorporated in place ofthe flap style contact 22.

The electrical conductors 20 can be assembled into an array (not shown)for incorporation into a molded connector. The array is assembled usingknown techniques. Forming of the electrical connector then takes placeusing known molding techniques with a suitable insulating material, orcombination of materials. Although the electrical connector is actuallyformed from molded plastic, the electrical connector is referred to asthe “pre-mold.” This reference is made for convenience, as the pre-moldconnector is later incorporated into a second molding. The secondmolding produces the FEC 100, which is an integrated component of theIFS 1. The second molding is produced using “over-mold” material, in an“over-molding” process.

The Pre-Mold Electrical Connector

Forming the electrical connector involves molding a body around thearray, where the array is jacketed with a suitably chemically andelectrically resistive plastic material. In one embodiment,polyoxymethylene (POM) is used to finish the array into a pre-moldelectrical connector 40, as shown in FIG. 6.

The pre-mold electrical connector 40 is shown in FIG. 6. The electricalconnector 40 shown in FIG. 6 shows the top portion of the array ofelectrical conductors 20. In FIG. 6, the male contact 21 is shownprotruding from the electrical connector 40 with the top most portion ofeach electrical conductor 20. Once assembled, the electrical connector40 also makes use of the torturous path technique for impeding thepassage of a fluid through the space between the electrical connector 40and the FCS 1. That is, a second series of ribs 26 is incorporated intothe trunk of the electrical connector 40 and form a second torturouspath, when considered with the first torturous path provided between theconductor 20 and the body of the electrical connector 40. The secondseries of ribs 26 in the electrical connector 40 are also shown in FIGS.7-8.

FIG. 7 is a side cross-sectional view of the pre-mold or electricalconnector 40. This view shows an electrical conductor 20, and shows boththe first series of ribs 25, and the second series of ribs 26. Whentaken in combination with FIG. 7, FIG. 8 shows that the second series ofribs 26 circumscribe the electrical connector 40.

In the preferred embodiment, the electrical connector 40 has a length(L) of about 50 millimeters (mm), with a base height (H) of about 11.4mm. The electrical connector 40 contains 4 electrical conductors 20. Sixof the ribs in the second series of ribs 26 are about 2 mm in width(RW), each being evenly spaced from the others, by a distance of about 1mm. The electrical connector 40 further contains a series of “meltribs.”

The melt ribs incorporated into the electrical connector 40 provide afurther impediment to the flow of fluids. The “melt ribs” are shown inFIG. 9. FIG. 9-1 identifies one embodiment where melt ribs 42 arelocated on the second series of ribs 26. The melt rib 42 is shown in theenlarged partial view of FIG. 9-2. In FIG. 9-2 a melt rib 42 is formedas excess plastic on the rib.

The melt rib 42 shown on the electrical connector 40 is added to supplyadditional sealing. The use of melt ribs 42 adds thin ribs of materialover the second series of ribs 26 of the electrical connector 40. Themelt ribs 42 melt during the over-molding process, mix, fuse andre-solidify with the over mold plastic, thus creating an additional sealbetween the electrical connector 40 and the over mold plastic used tocreate the FEC 100 shown in FIG. 1. In one embodiment, the melt ribs 42circumscribe the electrical connector 40, just as the ribs 25circumscribe the electrical connector 40.

In the preferred embodiment, where the pre-mold electrical connector 40is formed of POM, the melt ribs are designed to melt at the meltingpoint of the POM, or about 165° C. to about 177° C. Once the melt ribshave been heated to the melting point of the material used in theelectrical connector 40, the melt ribs flow and mix with the over-moldmaterial. The flow of materials between the electrical connector 40 andthe over-mold provides for an improved seal.

In various embodiments, the melt ribs 42 may appear on each rib in thesecond series of ribs 26, limited numbers of the ribs, or on otherportions of the electrical connector 40. The location for each of themelt ribs 42 on the electrical connector 40 may be determined by factorsthat include, but are not limited to, temperature, pressure andviscosity of the fluid.

In some embodiments, the pre-mold electrical connector 40 may be furthersubjected to a process of “impregnation” before incorporation into theover-mold 100. Impregnation is employed to even further increase theintegrity of the seal between the electrical connector 40, and theover-mold material used in the FEC 100. In embodiments whereimpregnation is included, an intermediate material is applied over theelectrical connector 40. In these embodiments, the electrical connector40 is placed into a vacuum chamber and sealed. The intermediate materialis pumped into the chamber until the material just covers the electricalconnector 40 while leaving the electrical contacts exposed. Pressure isreduced in the vacuum chamber to encourage the migration of air or othergas bubbles from the electrical connector 40, as well as from theintermediate material. In this manner, the intermediate material fillsvoids and improves the characteristics of the electrical connector 40.Afterward, the vacuum is relieved, and the sudden rush of gas appliespressure to the intermediate material, further seating the intermediatematerial over the electrical connector 40.

In an example of impregnation, and where the FEC 100 is used in the fuelenvironment, a highly chemically resistive plastic is selected forforming the FEC 100. In this exemplary embodiment, a commerciallyavailable product, LOCTITE 5110™ can be used as the intermediatematerial. LOCTITE 5110 ™ is a dimethacrylate type chemical that can beused as an electrical grade anaerobic sealant, and cures to form a toughthermoplastic in the form of a cross-linked acrylic. The materialprovides for excellent electrical insulation while being used in harshenvironments including long term exposure to solvents. Once theintermediate material is impregnated into the electrical connector 40,the excess material is removed. In various other embodiments, apolymeric material other than LOCTITE 5110™ is used as the intermediatematerial.

In this exemplary embodiment, use of LOCTITE 5110™ as an intermediatematerial provides for certain useful or advantageous properties. Forexample, the LOCTITE 5110™ remains uncured, or substantially uncured, inthe presence of air. Once the pre-mold 40 has been included into thepost-mold, the intermediate material is no longer exposed to air. As aresult, the curing process occurs once the pre-mold 40 is in the finalconfiguration as a FEC 100. A further advantage is realized by the sameproperty of the intermediate material. That is, excess intermediatematerial, such as material covering the electrical contacts 21, 22 maybe easily removed by a suitable wash.

After the electrical connector 40 is subjected to impregnation, or not,as the case may be, the electrical connector 40 is next incorporatedinto an over-mold in order to create a FEC 100.

The Flange Electrical Connector 100

After the pre-mold electrical connector 40 is formed, it is incorporatedinto a final molding, or post-mold, thereby forming a FEC 100. Thepost-mold may include the pre-mold electrical connector 40 with othercomponents or features to provide for an Integrated Flange Seal 1, orIFS 1, such as the fuel flange connector shown in FIG. 1. In otherembodiments, the post-mold may incorporate the pre-mold electricalconnector 40 into a form that is designed to mate with a system otherthan a fuel system, without incorporating other devices or features. Theactual configuration of the FEC 100, and the IFS 1 are dependent upon avariety of factors, including, but not limited to, the needs of theuser.

The FEC 100 is shown in FIG. 10. In FIG. 10, the FEC 100 is incorporatedinto an Integrated Flange Seal 1, or IFS 1. The IFS 1 shown furtherincludes a separate penetration 60, in this case the penetration 60being for a fuel line connection (not shown).

Once the pre-mold electrical connector 40 is incorporated into thepost-mold FEC 100, the second series of ribs 26 define a secondtorturous path. This second torturous path provides the same designadvantages as the first torturous path, namely, the second torturouspath provides an impediment to the passage of foreign matter. The use ofthe same materials, or substantially similar materials, in the pre-moldelectrical connector 40 and post-mold FEC 100, further provide foreffective sealing of the FEC 100.

The combination of a dual torturous path design with the use of meltribs 42 thus provides for a highly effective seal in an electricalconnector 40 useful for impeding the passage of fluids includinghydrocarbon based fuel components. In various embodiments, theconstruction of the electrical connector 40 further using impregnationprovides for additional sealing effectiveness.

The combination of the dual torturous path design with the use ofimpregnation thus also provides for a highly effective seal in anelectrical connector 40 useful for impeding the passage of fluidsincluding hydrocarbon based fuel components. In various embodiments, theconstruction of the electrical connector 40 further using melt ribsprovides for additional sealing effectiveness.

It should be understood that the foregoing description and embodimentsare only illustrative of the invention. It should further be recognizedby one skilled in the art that while the teachings herein have beenexpressed in terms of a FEC 100 for an automobile, a variety ofembodiments and applications are possible while remaining within theteachings of this invention. For example, the FEC 100 could be used toprovide a sealed electrical connection to a system containing fluids,such as but not limited to, insecticide or pesticides.

A variety of factors that may be varied in order to realize otherembodiments include, but are not limited to, characteristics of thetorturous path, including appearance and number of features in thepathway; the number, placement and volume of the melt ribs; propertiesof material selected for impregnation; pressure and duration of theimpregnation technique; size, number and conductivity of the electricalconductors 20; arrangement or electrical separation of the electricalconductors 20; properties of materials selected for coating ofelectrical conductors 20, the pre-mold electrical connector 40, or thepost-mold FEC 100; sealing efficiency requirements; post-mold FEC 100applications, and properties of the environment.

1. A method for forming an electrical connector, the method comprising: providing at least one electrical conductor comprising a first plurality of ribs; jacketing said at least one electrical conductor with an electrical insulating material to form a connector body, wherein said first plurality of ribs defines a first tortuous path with said electrical insulating material for impeding the passage of fluid, said connector body comprising a second plurality of ribs for defining a second tortuous path for impeding passage of fluid between said connector body and a surrounding structure within which at least a portion of said connector body is disposed after said connector body is formed, wherein said second plurality of ribs comprise melt ribs formed when said second plurality of ribs is formed.
 2. The method as in claim 1, wherein said electrical insulating material comprises polyoxymethylene.
 3. The method as in claim 1, wherein said fluid comprises a hydrocarbon based fuel.
 4. The method as in claim 1, further comprising: impregnating a coating onto the connector body.
 5. The method as in claim 4, wherein said coating comprises dimethylacrylate.
 6. A method for forming a fuel flange, the method comprising: providing at least one electrical conductor comprising a first plurality of ribs; jacketing said at least one electrical conductor with an electrical insulating material to form a connector body, said first plurality of ribs defining a first tortuous path with said electrical insulating material for impeding the passage of hydrocarbon based fuel components, said connector body comprising a second plurality of ribs comprising a substantially uniform series of ribs looping around an exterior of the connector body; and, molding said fuel flange around said connector body for forming a second tortuous path, said second plurality of ribs defining said second tortuous path for impeding passage of hydrocarbon based fuel components between said connector body and said fuel flange.
 7. The method as in claim 6, where said second plurality of ribs comprises melt ribs.
 8. The method as in claim 6, where said electrical insulating material comprises polyoxymethylene.
 9. The method as in claim 6, further comprising: impregnating a coating over said connector body.
 10. The method as in claim 6, wherein said coating comprises dimethylacrylate.
 11. A method of forming a vehicle fuel tank combined fuel flange and electrical connector comprising: molding a pre-mold housing onto a plurality of electrical conductors to form a pre-mold electrical connector, wherein the electrical conductors comprising ribs such that first tortuous joints are formed between the pre-mold housing and the electrical conductors; and overmolding a flange member onto the pre-mold electrical connector, wherein the pre-mold housing comprises a series of circumferential ribs on an exterior side which form a second tortuous joint between the flange member and the pre-mold electrical connector.
 12. A method as in claim 11 wherein the step of overmolding comprises overmolding a portion of the flange member onto the electrical conductors.
 13. A method as in claim 11 wherein the electrical conductors comprise right angle contacts and the pre-mold housing is molded onto a bend of the right angle contacts.
 14. A method as in claim 13 wherein the right angle contacts comprise a male contact portion at a first end and a flap contact portion at an opposite second end, and wherein the pre-mold housing is molded onto the flap contact portion.
 15. A method as in claim 11 wherein molding of the pre-mold housing comprises forming melt ribs on the ribs of the pre-mold housing.
 16. A method as in claim 11 further comprising impregnating the pre-mold housing with a sealing material.
 17. A method as in claim 16 wherein the step of impregnating occurs before the flange member is overmolded onto the pre-mold electrical connector.
 18. A method as in claim 16 wherein the step of impregnating comprises use of a material which remains substantially uncured in the presence of air. 